The invention relates to an optoelectronic device for detecting markings affixed to objects by using a transmitter that emits light rays, a receiver that receives light rays, an evaluation device and a deflection unit.
Devices of this type in particular can be designed as barcode readers. These barcode readers can detect, for example, barcodes affixed to the top surfaces of objects transported along on a conveyor belt, such as packages or the like. For detecting the barcodes on the top surfaces of the objects, the barcode reader is thus installed above the conveyor belt and above the objects.
However, problems can arise in cases where the orientation of barcodes affixed to objects is not clearly given, relative to the barcode reader.
Objects of this type are, for example, sample tubes used in medical technology, which are moved along the conveyor belt while standing in an upright position.
The sample tubes contain blood samples, urine samples, serum samples or the like, which are marked with a barcode on the surface area of the sample tube.
An optoelectronic device designed as barcode reader is used to detect the barcodes and identify the samples, which device is installed stationary on the side of the conveyor belt.
The disadvantage of this configuration is that the barcode reader can detect the barcodes on a sample only if the barcode reader is directed toward this barcode. Detection is not possible, however, if the barcode is on the side facing away from the barcode reader.
To avoid a faulty detection, the sample tube could respectively be turned so that the barcode is located on the side of the sample tube that is facing the barcode reader.
However, turning the sample tube in this way would require an undesirably high manual expenditure and a correspondingly high use of personnel.
A device for automatically turning the sample tubes would require an additional sensor-controlled device, thereby resulting in considerable cost expenditure.
It is the object of the invention to design a device of the aforementioned type in such a way that it can detect markings with certainty in a different spatial orientation to the device.
This object is solved with an optoelectronic device according to the invention comprising a deflection unit, which is followed by at least two reflecting units. By way of the deflection unit, the transmitting light rays are periodically guided inside a predetermined angular range xcex94xcex1. Inside a first segment xcex94xcex11 of the angular range xcex94xcex1, the transmitting light rays are guided over the first reflecting unit, so that these rays periodically scan a first section of a three-dimensional detection range. Inside a second segment xcex94xcex12 of the angular range xcex94xcex1, the transmitting light rays are guided over the second reflecting unit, so that these rays periodically scan a second section of the detection range.
The object with the marking arranged thereon is preferably introduced to the detection range by means of a conveyor.
The transmitting light rays are guided via the reflecting units and at differing angles of incidence onto the object surface, so that markings with differing orientation on the object surface can be detected with certainty.
Since the detection range is a three-dimensional area, the markings can also be arranged on an object surface extending in a three-dimensional space and can still be detected with certainty.
In particular, the objects can be sample tubes transported along on a conveyor belt that serves as conveying device. For this, the sample tubes are preferably positioned such that they stand upright on the conveyor belt, wherein the barcodes can be affixed at optional angular positions on the surface area of the sample tubes. The longitudinal axes of the barcodes preferably extend in longitudinal direction of the sample tubes. Since the transmitting light rays are guided at different angles of incidence over the surface area of the complete circumference of the sample tubes and preferably scan this surface area in longitudinal direction, the barcode can be detected with certainty at optional angular positions, without requiring a realignment of the sample tubes.